Hexaammonium molybdate Chemical Properties

Melting point:

190°C

Density 

2,498 g/cm³

storage temp. 

Store at RT.

solubility 

H₂O: soluble

form 

Liquid

Specific Gravity

2.498

color 

Clear light colored

Water Solubility 

Freely soluble in water.

Merck 

14,533

Exposure limits

ACGIH: TWA 0.5 mg/m3
NIOSH: IDLH 1000 mg/m3

Stability:

Stable.

CAS DataBase Reference

12027-67-7(CAS DataBase Reference)

EPA Substance Registry System

Molybdate (Mo7O246-), ammonium (1:6) (12027-67-7)

Safety Information

Hazard Codes 

Xi

Risk Statements 

22-36/38-52/53-36/37/38

Safety Statements 

26-36

RIDADR 

UN 3264

WGK Germany 

-

RTECS 

QA4900000

TSCA 

Yes

HS Code 

28417010

Hazardous Substances Data

12027-67-7(Hazardous Substances Data)

Toxicity

mic-esc 2 mmol/L MUREAV 31,185,1975

MSDS

• Language:English Provider:Hexaammonium molybdate
• Language:English Provider:ALFA

Hexaammonium molybdate Usage And Synthesis

Physical Properties

Colorless, monoclinic crystal; density 2.276 g/cm3; decomposes on heating; soluble in water (decomposes); also soluble in acid; insoluble in alcohol and liquid ammonia.

Uses

Ammonium molybdates are used to prepare high purity grade molybdenum metal powder, sheet, or wire; for colorimetric analysis of phosphates and arsenates; for decorating ceramics; and as catalysts.

Preparation

Ammonium molybdate is prepared by treating molybdenum oxide with excess ammonia in an aqueous solution. The crystals are obtained after evaporation of water.
MoO3 + 2NH3 + H2O → (NH4)2MoO4

Reactions

Decomposes on heating or on treatment with alkalies; reacts with lead chloride and other metal salts to form their metal molybdates:
(NH4)2MoO4 + PbCl2 → PbMoO4 + 2NH4Cl
Reacts with phosphates or arsenates to form ammonium phosphomolybdate (NH4)3PO4•12MoO3, or ammonium arsenomolybdate, (NH4)3AsO4•12MoO3.

Chemical Properties

Ammonium heptamolybdate is an odourless crystalline compound ranging in colour from white to yellow-green. It is usually encoutered as the tetrahydrate, whose chemical formula is (NH4)6Mo7O24·4H2O. It is often referred to simply as ammonium molybdate, although this name can also refer to ammonium orthomolybdate, (NH4)2MoO4, and several other species.

General Description

White to greenish-yellow solid. Sinks and mixes with water.

Air & Water Reactions

Water soluble.

Reactivity Profile

Salts, basic, such as Hexaammonium molybdate , are generally soluble in water. The resulting solutions contain moderate concentrations of hydroxide ions and have pH's greater than 7.0. They react as bases to neutralize acids. These neutralizations generate heat, but less or far less than is generated by neutralization of the bases in reactivity group 10 (Bases) and the neutralization of amines. They usually do not react as either oxidizing agents or reducing agents but such behavior is not impossible.

Health Hazard

Inhalation causes irritation of nose and throat. Contact with eyes causes irritation.

Fire Hazard

Special Hazards of Combustion Products: Toxic oxides of nitrogen may form in fire.

Flammability and Explosibility

Not classified

Agricultural Uses

Ammonium molybdate, (NH₄)₆MO₇O₂₄·2H₂O is an important molybdenum fertilizer. It is an ammonium salt of molybdic acid and contains about 50% molybdenum.
Ammonium molybdate is generally mixed with NPK fertilizers, depending on the crop requirement (generally 50 to l000 gm per ha). The fertilizer is also applied as a foliar spray, but coating or soaking seeds with ammonium molybdate is the easiest method of application, which requires very little fertilizer.

Safety Profile

Mutation data reported. Whenheated to decomposition it emits toxic vapors of Mo andNH3.

Hexaammonium molybdate (12027-67-7)Related Product Information

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